<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button type="button" id="btn1">注册1</button>
    <button type="button" id="btn2">注册2</button>
</body>
</html>
<script>
    var btn1 = document.getElementById("btn1");
    var btn2 = document.getElementById("btn2");
    window.onload = _=>{
        btn1.onclick = function(){
            this.innerHTML = "abc"
            console.log( this  );
        }
        btn2.onclick = ()=>{
            this.innerHTML = "abc"
            console.log( this  );
        }
    }

    const f=  (...rest) =>{
        console.log(rest );
    }
    
</script>